@phdthesis{Fix2007,
  author    = {Fix, Christian},
  title     = {Klinische Ergebnisse nach der operativen Versorgung von Glenoidrandfrakturen mittels kan{\"u}lierter Titanschrauben},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-26188},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2007},
  abstract  = {Die Notwendigkeit einer operativen Versorgung von Glenoidrandfrakturen des Typs I nach Ideberg bzw. kn{\"o}cherner Bankartfrakturen wird in der Literatur kontrovers diskutiert. Implantat bedingte Langzeitversager und Sp{\"a}tkomplikationen nach operativer Behandlung stehen im Gegensatz zu wiederholten Rezidivluxationen und Deformierungen der Glenoidoberfl{\"a}che mit der Gefahr von Sp{\"a}tarthrosen nach konservativer Therapie. In einer retrospektiven klinischen Studie wurden 32 Patienten, darunter neun Frauen (26,5\%) und 25 M{\"a}nner (73,5\%), mit einem Durchschnittsalter von 39,7 Jahren (16-77) nach einem mittleren Zeitraum von 42 Monaten (8-121) radiologisch und klinisch im Constant- (CS) und Rowe-Score (RS) sowie mittels Simple-Shoulder-Test nachuntersucht. S{\"a}mtliche Patienten berichteten {\"u}ber ein initial traumatisches Luxationsereignis mit nachfolgenden Rezidivluxationen unterschiedlicher H{\"a}ufigkeit. Die Indikation f{\"u}r die operative Versorgung mittels kan{\"u}lierter Titanschrauben nach Resch umfasste große, dislozierte Glenoidrandfrakturen mit einer Beteiligung von mindestens 15\% des Gelenkfl{\"a}chendurchmessers. Neben der Darstellung der Gesamtergebnisse im Kollektiv wurden mehrere Gruppen unterschieden: eine Untergruppe ohne schwerwiegende Begleitverletzungen (RM-(teil)-Ruptur oder Tuberculum majus-Fraktur, n=16, Gruppe 1A) und eine Untergruppe, bei welcher diese Begleitverletzungen vorlagen (n=16, Gruppe 1B). Eine weitere Unterscheidung erfolgte hinsichtlich des Lebensalters zum Zeitpunkt der Operation: Alter < 40 Jahre (n=19, Gruppe 2A) und Alter > 40 Jahre (n=13, Gruppe 2B). In keinem Fall traten Komplikationen durch die eingebrachten Schrauben auf. In einem Fall war eine Osteolyse des Fragmentes ohne Einfluss auf das funktionelle Ergebnis zu beobachten. Reluxationen oder erneute Operationen waren im gesamten Kollektiv nicht zu verzeichnen. S{\"a}mtliche Patienten konnten wieder zu ihrer urspr{\"u}nglichen Arbeitst{\"a}tigkeit zur{\"u}ckkehren und {\"a}ußerten sich zufrieden mit dem Operationsergebnis. Die Score-Mittelwerte im Gesamtkollektiv zeigten mit 82 Punkten (CS) und mit 85 Punkten (RS) gute, mit 92,3\% (korrigierter CS) sogar sehr gute Ergebnisse, obwohl diese Werte immer noch signifikant unter denen der nicht operierten Gegenseite lagen. Die Begleitverletzungen wirkten sich unter Ber{\"u}cksichtigung des h{\"o}heren Lebensalters in Gruppe 1B gegen{\"u}ber Gruppe 1A (44 Jahre vs. 36 Jahre) signifikant auf das funktionelle Ergebnis aus: diejenigen Patienten, welche eine Rotatorenmanschetten-L{\"a}sion oder eine Fraktur des Tuberculum maius aufwiesen, zeigten im Rowe-Score sowie im Simple-Shoulder-Test signifikant niedrigere und im Constant-Score tendenziell niedrigere Werte als diejenigen ohne die genannten Begleitverletzungen. Auch die angenommene Korrelation von Lebensalter und funktionellem Ergebnis konnte f{\"u}r das vorliegende Patientengut best{\"a}tigt werden. Das j{\"u}ngere Teilkollektiv wies in Rowe-Score, Constant-Score und Simple-Shoulder-Test signifikant h{\"o}here Durchschnittswerte auf als das {\"a}ltere. Ein direkter Zusammenhang zwischen dem Lebensalter und der H{\"a}ufigkeit bestimmter Begleitverletzungen wird angenommen, kann aber anhand des vorliegenden Patientenkollektives statistisch nicht best{\"a}tigt werden. Glenoidrandfrakturen treten insbesondere nach Schulterluxationen im mittleren Lebensalter auf und sind h{\"a}ufig mit schwerwiegenden Begleitverletzungen assoziiert. Die Versorgung mittels kan{\"u}lierter Minischrauben nach Resch erwies sich in unseren Augen als komplikationsarmes Verfahren mit guten bis sehr guten mittelfristigen Ergebnissen und stellt somit eine Erfolg versprechende Therapieoption dar.},
  subject      = {Schultergelenk},
  language  = {de}
}
@phdthesis{Bockmeyer2007,
  author    = {Bockmeyer, Matthias},
  title     = {Structure and Densification of Thin Films Prepared From Soluble Precursor Powders by Sol-Gel Processing},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-24577},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2007},
  abstract  = {The main focus of this work was to get a deeper understanding of the relationship between the structure of sol-gel films, their densification and their macroscopic cracking. First of all titania was chosen as model system. Therefore a synthesis route starting from the preparation of long-term stable amorphous redissoluble precursor powders based on acetylacetone as chelate ligand was utilized. The solubility and stability of the powders in various solvents can be determined by chemical synthesis and technological parameters. When dissolved in a solvent mixture of ethanol and 1,5-pentanediol, thin films can be easily prepared by dip-coating technique. Thereby the quality of the titania films enormously depends on the calcinations temperature and the solvent mixture is used. In order to investigate the influence of different solvents and solvent mixtures on the microstructure and densification of the precursors, the coating solutions were stripped off (sol powder) and analyzed as function of annealing temperature. It was pointed out that a high densification rate caused by the addition of 1,5-pentanediol, results in dense microstructure with trapped residual carbon. These impurities can retard the phase transformation of anatase to rutile. The analysis of so-called "film powders" scraped off multiple dip-coated substrates provides valuable information on the effect of air moisture and unidirectional densification during drying and aging on the structure of thin films. The high surface-to-volume ratio and access to air moisture determine the chemical composition of the as-prepared film, which controls shrinkage, crystallization and defect structure of the coatings. Further it was shown, that drying as a thin film results in the formation of closed pores and much denser microstructure than the respective sol powder. Without the addition of 1,5-pentanediol all -OEt moieties undergo hydrolysis reactions, which causes the formation of a rigid network. The presence of 1,5-pentanediol retards this hydrolysis reactions and provides some network plasticity. Generally the microstructure of thin films is comparatively close to the microstructure of the film powders. The addition of 1,5-pentandiol prevents hydrolysis and condensation reactions as like in the film powders. However even at 700 °C, thin films never transform to rutile, which was attributed to the tensile stresses in thin films. In thin films and in film powders as well a comparable amount of closed pores are formed during annealing. Further it was shown that most of the thin sol-gel films investigated form a dense crust on their tops during annealing. This explains why crack free films exhibit only closed pores. However, when cracks appear during thin film shrinkage in the coating, this crust is burst, which generates open porosity. The defect density in the coatings was determined by an automated analysis of surface images. The crack formation and quantity can be directly referred to tensile stresses in the coatings, which arise from hydrolysis and condensation during thin film drying and aging. Therefore when 1,5-pentanediol is added to the sol, thin film cracking was avoided, because hydrolysis and condensation reactions are retarded, which preserves a higher network flexibility. Furthermore the crack formation was significantly influenced by the atmospheric humidity that was used during the coating process, which was explained by different drying and condensation rates. Under certain chemical starting conditions water soluble precursor powders can be also obtained. In general the observations made with the water based coating solutions are mostly in agreement with the former results based on ethanol based coating solutions. For example the high surface-to-volume ratio of film powders compared to sol powders also significantly enhances film drying and densification. The addition of 1,5-pentanediol also clearly contributes to their densification behavior and phase evolution. As seen before in the case of ethanol based coatings, 1,5-pentanediol enhances the stability towards hydrolysis and condensation reactions and preserves some network plasticity. Therefore coatings prepared without the addition of 1,5-pentanediol already form cracks during film drying and aging because of tensile stresses. Thus, the addition of 1,5-pentanediol results in a reduction/prevention of crack formation. Nevertheless some differences were observed, i.e. the critical single coating film thickness of ethanol based coatings is nearly twice that of water based coatings. This was explained by the different surface tensions of the basis solvents, which during thin film drying causes significantly higher capillary forces and tensile stresses in water based coatings. When acetylacetone is replaced by triethanolamine as chelating ligand for titanium also re-dissolvable precursor powders can be synthesized. The film powders combine a high hydrolytic stability of the precursor with sufficient intermediate network flexibility. The different type of organics changes the drying and densification behavior: i.e. in contrast to film powders obtained from acetylacetone based precursor powders the structure of triethanolamine based film powders is unaffected by the thin film drying process. This high hydrolytic stability and plasticity of this precursor allows the preparation of defect free coatings up to single film thickness of 300 nm. However triethanolamine based thin films present at intermediary annealing temperatures a distinctively different microstructure compared to acetylacetone based films. The general validity of the conclusions was proved on the basis of zirconia coatings that were also prepared by the use of re-dissolvable precursor powders. In principle all conclusions concerning the interconnection of precursor chemistry, film formation, densification and structure were transferable to the respective zirconia coatings. Differences mainly arise only from differential material properties i.e. bulk density. Finally, it has been pointed out that the findings obtained on the densification behavior of thinsol-gel films are also a valuable tool for improved explanations of other important scientific questions concerning sol-gel films, i.e. scratch resistance of sol-gel coatings, fiber -bridging and - degradation of sol-gel coated fibers.},
  subject      = {Sol-Gel-Verfahren},
  language  = {en}
}